Method of making piston rings



R. GROVER METHOD OF MAKING PISTON RINGS Filed Feb. 27. 1922 I M/vEgTaR. ATTORNEY.

Patented Dec. 1, 1925.

warren sraras RAY GROVEBI, OF MIL-"JZAUKEE, WISCONSIN.

METHOD OF iii/TAKING FISTON RING-S.

Application filed February 27, 1922. Serial No. 539,487.

1/ "0 all whom it may concern:

Be it known that I, RAY Gaovnn, a citizen of the United States, residing at Milwaukee, county of Milwaukee, and State of Nisconsin, have invented new and useful Improvements in Methods of Making Piston Rings, of which thefollowing is a specification.

This invention relates to piston rings and to the method of making piston rings of that class in which resilient, expansible split rings are shaped at their ends to interlap at the joint when contracted in a piston groove.

One object of my invention is to provide an improved method of making piston rings, whereby a more effective packing may be secured, and whereby the cost of production may be reduced, and the manufacture of the rings expedited.

rurther objects are to produce a cheaper, more effective, and better packing ring than has heretofore been made, to eliminate carbon troubles and compression leaks at the oints and to ensure accurate registry of the ends of the ring with each other.

In the accompanying dra'wings,-

Figure 1 is a side elevation of the improved piston rin Figure 2 is a fragmentary view showing a portion of the ring as it appears after the initial cutting and splitting operations.

Fi ure 3 is a perspective view of similar fragments in a subsequent stage of production, with the abutting ends partially offset laterally with reference to each other, and with the exposed portions cut or milled away to form recesses and tongues adapted to interlap and engage in the recesses when the ring is contracted.

Figure 4 is a similar view with the parts restored to normal position.

Figure is a plan. view of the parts show in Figure a.

Figure 6 is a perspective view of the in terlapping end portions of the ring when contracted in position for use.

Like parts are identified by the same reference characters throughout the several views. 7

In practicing the improved process a continuous ring composed of resilient material is first machined out for a short distance along its inner face to forin an interior recess 2. The relatively thin web of remaining material is then severed transversely at or near the middle of the. recess, thereby splitting the ring as illustratedin Figure 2.

shown in Figure 3, the exposed half of the.

web will be cut away on opposite sides of thejoint 3, and recesses will be formed in the outer surface of the ring beyond the ends of the interior recess 2 of a depth equal to the thickness of the web. The bottom surfaces 4 and 5 of these recessesform bearing surfaces to receive the tongues 6 and 7 which comprise the remaining portions of the web, when the end portions of the ring arereturned to normal position and the ring contracted as illustrated in Figures 1 and 6.

The method above described enables me to employ ordinary cutters or milling tools. After the ends of the ring are ofi'set as above described it is obvious that the cutting operation may commence at the ends of the ring thus exposed and the cutting operation proceed along the longitudinal line of the ring, to a distance beyond the end of the recess 2 on each side of the joint 3 equal to or a little in excess of the length of the tongues 6 and thus formed the depth of the cutwill pref erably be progressively lessened, thereby forming the curved surfaces 8, which terminate inthe outer surfacelO of the ring. The ends of the notch, however, are beyond the field of movement of the interlapping tongues 6 and 7 when the ring is contracted as illustrated in Figure 6, andtherefore the form of the surface 8 is not regardedas 1naterial. The base 4 of the recess constitutes the inner bearing face for the tongue 7, and the base 5 of the opposing recess forms the corresponding bearing surface for the tongue 6. Each of the tongues 6 and 7 also bear upon each other along their inner side faces 9.

It will be understood that the depth of the inner recess 2 practically determines the depth to which the outersurface of the ring is to be cut away on each side after offsetting the ends as above explained inasmuch as the 7. At the ends of the notches bearing surfaces 4 and 5 should be virtually continuous with the under surfaces of the tongues 6 and 7. It is therefore desirable that the depth of the notch 2 should be substantially equal to one-half of the original thickness of the ring, the depth of the cut in the outer surface of the ring being equal to that of the recess 2, although but one-half of the width thereof. It follows that the tongues 6 and 7, will, when the ring is compressed, be adapted to take the place of the material which has been cut away above the surfaces or ledges 4 and 5 to the extent to which such tongues bear upon said surfaces.

After the final milling operation, the ends of the ring are returned to normal position as illustrated in Figures 4 and 5, whereupon the ring is ready for commercial sale. But when the ring is applied to a piston it will be contracted by compression until the tongues 6 and 7 interlap and bear upon the surfaces 4 and 5 as shown in Figures 1 and 6. lVhile held in such position within the pi ton grooves the piston may be inserted in a cylinder, the wall of which retains the ring in the usual manner.

It is to be noted that the inner side surfaces of the tongues 6 and 7 arefinished machine surfaces and are held-by the gas pressure in the cylinder in intimate contact with each other, thereby preventing passage or leaking of the gas through such joint. It is also to be noted that the tongues 6 and 7 seat respectively upon the webs 4 and 5 and form an eflicient joint to prevent passage of the gases inwardly toward the grooves within which the rings are positioned. In addition to this, the ringsare seated against the appropriate side of the piston groove by the gas pressure and thereby complete the sealing.

It is to be further noted that when the ring is contracted, the adjacent or relatively movable ends of the ring are held against radial movement, as the interlocking of the tongues 6 and 7 with the webs 4 and 5 prevent motion of either end inwardly or outwardly along radial lines.

It has been found in actual practice that after continued and protracted use, there is no carbon deposit between the tongues 6 and 7 Or between'such tongues and the webs 4 and 5 respectively, but that suchsurfaces are bright and polished, showing, therefore, a perfect gas-tight seating.

Great importance is attached to the feature of my process which involves offsetting the ring ends relatively to each other after the initial formation of the recess 2, and the severing operation at 3. By offsetting the ring ends to allow an ordinary milling cutter to commence operations at the extremity of the exposed end or end portion, it becomes possible to employ a simple rotary milling cutter for this purpose, the circular form of the cutter (upon completing its operation) produces theinclined surface 8. Then the ring may be reversed in position and the same cutter employed to remove a corresponding portion from the other exposed end of the ring. The bearing surfaces 4 and 5, and also the surfaces 9 being accurately machined during the cutting operation, no special tools or expensive equipment are required. But the work may be done much more quickly than has been possible in the manufacture of other rings of this general type.

ln the completed ring the end walls of the recess 2 form shoulders 12 and 13 which extend entirely across the ring and these shoul ders are in close proximity when the ring is contracted in position for use although they are separated adistance equal to the length of the recess 2 when the ringis permitted to expand to its normal size. The slight expansion and contraction of the ring within a cylinder which. has worn to a slightly conical form causes the overlapping tongues 6 and 7 and the surfaces 4, 5, and 9 of the ledges to wear true and these surfaces become highly polished and closely fitting. The tongues 6 and 7 being on the outer or peripl'ieral half of the ring. receive the full pressure of the gases to hold them in continuous side to side contact.

I claim 1. The process of making a piston ring having a stepped, sealed joint, said process comprising thinning a portion of such ring from the inside towards the outside, severing said ring at the thinned portion, deflecting the adjacent free ends of'the ring laterally, and forming outwardly projecting tongues and an adjacent thinned portion.

2. The process of making a piston ring having a stepped, sealed joint, said process comprising removing a portion of the ring from the inner side and. leaving a web, severing said web, deflecting laterally the resulting free ends, and machining away a portion of said web to form alternately arranged projecting tongues and associated webs, and finishing the juxtaposed faces of said tongues and webs at a single operation.

3. Theprocess of cutting peripheral marginal grooves in a split ring, said process including the warping of the abutting. ends of the split ring to expose the end of the portion to be grooved, and the subsequent cutting away of the material of the exposed portion to produce a groove of the desired depth by a cutting movement along a. line substantially paralleling the margin of the ring.

4, The process of cutting marginal peripheral grooves in a split ring, said process including warping the ring to produce relative lateral deflection of the abutting ends thereof. whereby the end surfaces of the portions to be removed are exposed, and-the subsequent cutting of the exposed material beginning at the end surfaces aforesaid and at'a depth equivalent to a portion of the thickness of the ring and working thence peripherally about the ring for the desired length of cut.

5. The process of making a piston ring having a stepped, sealed joint, said process comprising removing a portion of the ring from the inner side, whereby to leave an outer peripheral web, severing said web, warping the ring to producerelative deflection of the resulting free ends, whereby to expose a portion of the end surface of each of said free ends, and machining away the exposed portion of each web and a portion of the abutting stock of the ring substantially equal in width and depth to the web portion so removed.

6. The process of making apiston ring having a stepped, sealed joint, said process comprising removing a portion of the ring approximately one-half the thickness thereof from the inside leaving substantially square shoulders abutting the cut so made, and a peripheral web exterior to said cut, severing said web substantially midway between said shoulders, deflecting the resulting free ends laterally to substantially one-half their width, whereby substantially one-half of the end surface of each of said web ends is exposed, and machining away the exposed portion of each of said webs and a portion of the adjacent stock of the ring substantially equal in width, depth and peripheral extent to the portion of the web so removed.

7. The process of making a piston ring having a stepped, sealed joint, said process comprising the severing of a ring to produce free ends, and the cutting of peripheral marginal portions of the ring by beginning at a desired point and depth and thence working circumferentially to the desired extent with at. least a portion of the lines of out being at said ends of the ring and thereat substantially paralleling the ring margin, whereby each of the ends will have an uncut portion with square corners.

8. The process of making a piston ring having a stepped, sealed joint, said process comprising the removal of outer peripheral marginal portions of material of a split ring starting at the free ends thereof with a line of cut substantially parallel to the margin of the ring and working circumferentially to the desired point whereby each of the free ends of the ring will have an uncut portion with square corners.

9. The process of making a piston ring having a stepped, sealed joint, said process comprising the removal of peripheral marginal portions of the material of a split ring beginning at a desired point and depth on each side of the split and then Working circumfer'entially vwith the entire line of cut substantially paralleling the margin of the ring whereby each of the ends of the ring will have an' uncut portion with square corners and the-side wall of the cut away portion will substantially parallel the margin of the ring, at least a portion of said cuts being at the free ends. V

10. The process of making a piston ring having a stepped, sealed joint, said process comprising theremoval of peripheral marginal portions of material of a split ring starting at the ends thereof with lines of cut substantially parallel to the margin of the ring and working circumferentially to the desired point, the entire lines of cut substantially paralleling the margin of the ring whereby each of the ends of the ring will have an uncut portion with square corners, and the side wall of the cut-out portion will parallel the ring margin.

11. The process of making a piston ring having a stepped, sealed joint, said process comprising, in suitable order, the following steps: the thinning of the ring from the interior thereof to a depth approximately onehalf the thickness of the finished ring, the severing of the ring to produce free ends where it is thinned, and the cutting of peripheral marginal portions of the ring beginning at said ends and thence working circumferentially along a line of out which throughout its length parallels the margin of the ring, and which in length is substantially twice the circumferential extent of said thinned portions, said out having a depth substantially equal to the thickness of the portions so thinned.

12. The process of making a piston ring having a stepped, sealed joint, said process comprising the following steps in suitableorder: thinning the ring from the center outwardly, severing the ring to produce free thinned ends whereby the thinned portion will be on opposite sides of the line of severance, laterally deflecting the thinned ends of the ring to expose portions of their end surfaces, and milling circumferentially from each of said ends upon opposite sides of said ring.

13. The process of making a piston ring having a stepped, sealed joint, said process comprising the following steps in suitable order: thinning a portion of the ring from the center outwardly, severing the ring along a substantially straight line of severance to produce free ends, the free ends being within the thinned portion of the ring whereby there are provided free thinned ends, and milling circumferentially directly from each of said ends upon opposite sides of said ring and along its outer peripheral margins with lines of out which at the ring ends substantially parallel the margins of the ring, said lines of out being of a depth approximately the thickness of the thinned ends of the ring.

14. The process of making a piston ring having a stepped, sealed joint, said portion comprising the following steps in suitable order: thinning a portion of the ring from the center outwardly, severing the ring along a substantially straight line of severanceto produce tree ends, the, free ends being within the thinned portion whereby they are thinned, and milling circumferentially from each of said ends upon opposite sides of the ring to a depth approximately the thickness of the thinned ends of the ring, and to a circumferential extent approximately twice the length of the thinned ends of the ring, said lines of cut at the ends of the ring substantially paralleling the margins of the ring whereby each of said ends will have an uncut portion with square corners.

RAY GROVER. 

